diff options
Diffstat (limited to 'Lib/fontTools/misc/eexec.py')
| -rw-r--r-- | Lib/fontTools/misc/eexec.py | 166 |
1 files changed, 86 insertions, 80 deletions
diff --git a/Lib/fontTools/misc/eexec.py b/Lib/fontTools/misc/eexec.py index d1d4bb6a..cafa312c 100644 --- a/Lib/fontTools/misc/eexec.py +++ b/Lib/fontTools/misc/eexec.py @@ -16,98 +16,104 @@ from fontTools.misc.textTools import bytechr, bytesjoin, byteord def _decryptChar(cipher, R): - cipher = byteord(cipher) - plain = ( (cipher ^ (R>>8)) ) & 0xFF - R = ( (cipher + R) * 52845 + 22719 ) & 0xFFFF - return bytechr(plain), R + cipher = byteord(cipher) + plain = ((cipher ^ (R >> 8))) & 0xFF + R = ((cipher + R) * 52845 + 22719) & 0xFFFF + return bytechr(plain), R + def _encryptChar(plain, R): - plain = byteord(plain) - cipher = ( (plain ^ (R>>8)) ) & 0xFF - R = ( (cipher + R) * 52845 + 22719 ) & 0xFFFF - return bytechr(cipher), R + plain = byteord(plain) + cipher = ((plain ^ (R >> 8))) & 0xFF + R = ((cipher + R) * 52845 + 22719) & 0xFFFF + return bytechr(cipher), R def decrypt(cipherstring, R): - r""" - Decrypts a string using the Type 1 encryption algorithm. - - Args: - cipherstring: String of ciphertext. - R: Initial key. - - Returns: - decryptedStr: Plaintext string. - R: Output key for subsequent decryptions. - - Examples:: - - >>> testStr = b"\0\0asdadads asds\265" - >>> decryptedStr, R = decrypt(testStr, 12321) - >>> decryptedStr == b'0d\nh\x15\xe8\xc4\xb2\x15\x1d\x108\x1a<6\xa1' - True - >>> R == 36142 - True - """ - plainList = [] - for cipher in cipherstring: - plain, R = _decryptChar(cipher, R) - plainList.append(plain) - plainstring = bytesjoin(plainList) - return plainstring, int(R) + r""" + Decrypts a string using the Type 1 encryption algorithm. + + Args: + cipherstring: String of ciphertext. + R: Initial key. + + Returns: + decryptedStr: Plaintext string. + R: Output key for subsequent decryptions. + + Examples:: + + >>> testStr = b"\0\0asdadads asds\265" + >>> decryptedStr, R = decrypt(testStr, 12321) + >>> decryptedStr == b'0d\nh\x15\xe8\xc4\xb2\x15\x1d\x108\x1a<6\xa1' + True + >>> R == 36142 + True + """ + plainList = [] + for cipher in cipherstring: + plain, R = _decryptChar(cipher, R) + plainList.append(plain) + plainstring = bytesjoin(plainList) + return plainstring, int(R) + def encrypt(plainstring, R): - r""" - Encrypts a string using the Type 1 encryption algorithm. - - Note that the algorithm as described in the Type 1 specification requires the - plaintext to be prefixed with a number of random bytes. (For ``eexec`` the - number of random bytes is set to 4.) This routine does *not* add the random - prefix to its input. - - Args: - plainstring: String of plaintext. - R: Initial key. - - Returns: - cipherstring: Ciphertext string. - R: Output key for subsequent encryptions. - - Examples:: - - >>> testStr = b"\0\0asdadads asds\265" - >>> decryptedStr, R = decrypt(testStr, 12321) - >>> decryptedStr == b'0d\nh\x15\xe8\xc4\xb2\x15\x1d\x108\x1a<6\xa1' - True - >>> R == 36142 - True - - >>> testStr = b'0d\nh\x15\xe8\xc4\xb2\x15\x1d\x108\x1a<6\xa1' - >>> encryptedStr, R = encrypt(testStr, 12321) - >>> encryptedStr == b"\0\0asdadads asds\265" - True - >>> R == 36142 - True - """ - cipherList = [] - for plain in plainstring: - cipher, R = _encryptChar(plain, R) - cipherList.append(cipher) - cipherstring = bytesjoin(cipherList) - return cipherstring, int(R) + r""" + Encrypts a string using the Type 1 encryption algorithm. + + Note that the algorithm as described in the Type 1 specification requires the + plaintext to be prefixed with a number of random bytes. (For ``eexec`` the + number of random bytes is set to 4.) This routine does *not* add the random + prefix to its input. + + Args: + plainstring: String of plaintext. + R: Initial key. + + Returns: + cipherstring: Ciphertext string. + R: Output key for subsequent encryptions. + + Examples:: + + >>> testStr = b"\0\0asdadads asds\265" + >>> decryptedStr, R = decrypt(testStr, 12321) + >>> decryptedStr == b'0d\nh\x15\xe8\xc4\xb2\x15\x1d\x108\x1a<6\xa1' + True + >>> R == 36142 + True + + >>> testStr = b'0d\nh\x15\xe8\xc4\xb2\x15\x1d\x108\x1a<6\xa1' + >>> encryptedStr, R = encrypt(testStr, 12321) + >>> encryptedStr == b"\0\0asdadads asds\265" + True + >>> R == 36142 + True + """ + cipherList = [] + for plain in plainstring: + cipher, R = _encryptChar(plain, R) + cipherList.append(cipher) + cipherstring = bytesjoin(cipherList) + return cipherstring, int(R) def hexString(s): - import binascii - return binascii.hexlify(s) + import binascii + + return binascii.hexlify(s) + def deHexString(h): - import binascii - h = bytesjoin(h.split()) - return binascii.unhexlify(h) + import binascii + + h = bytesjoin(h.split()) + return binascii.unhexlify(h) if __name__ == "__main__": - import sys - import doctest - sys.exit(doctest.testmod().failed) + import sys + import doctest + + sys.exit(doctest.testmod().failed) |